Learning about lithosphere-atmosphere interactions from the cryosphere

The European Project for Ice Coring in Antarctica (EPICA) has recently announced results confirming that the long-term regulation of carbon dioxide in the atmosphere is largely a geological phenomenon. Carbon dioxide is naturally introduced into the atmosphere through volcanic activity and naturally removed through the weathering of rock and the deposition of carbon-laden rock in deep ocean sediments.

On the basis of evidence collected from a 3270 metre Antarctic ice core, the EPICA team determined that the atmospheric concentration of carbon dioxide underwent a long-term change of 22 parts per million over the 610,000 years before industrialization. This period covers five complete glacial-interglacial cycles. Since the Industrial Revolution, however, concentrations have risen by about 100 ppm – an overall rate 14,000 times higher.

Probably the most important thing to take from this is that the current behaviour of the global carbon system is likely to be different from that which has been dominant across geological time, simply because such a huge volume of carbon dioxide has been released through the burning of fossil fuels and deforestation.